Unmetered 10+ gigabit connections were on the order of $1/mbit/mo wholesale over a decade ago when I priced out a custom CDN so for the cost of 100 TB of data transfer out of AWS you could get a 24/7 sustained 10gbit/s (>3 PB per month at 100% utilization).
Not all connections are created equal. Even some big providers clearly have iffy peering agreements upstream that’ll manifest as terrible performance if you have a widely-geographically-distributed bandwidth-heavy load.
That’s pretty expensive. Sonic offers 1-10gbps (depending on where you live) unmetered symmetric connections for $60/mo to the Bay Area… they’re also the only ISP that petitioned the FCC in favor of net neutrality.
For work I end up transferring 50-150 gigs often, sometimes daily. Never heard a word from them that this has been a problem.
If you host copies of your data with a few big providers could you do something smart like detect and redirect requests from AWS to an S3 bucket and not pay for bandwidth leaving the provider?
Bandwidth has always been crazy cheap.